1. Field of the Invention
The present invention pertains to microwave integrated circuit (MIC) open ring-resonator oscillator-combiners using negative impedance diodes, and more particularly to such MIC devices having reduced sensitivity to mismatches between the active negative impedance driving devices.
2. Description of the Prior Art
In a prior U.S. patent application, Ser. No. 904,698, filed May 10, 1978, now U.S. Pat. No. 4,185,252, and incorporated herein by reference, the present inventor discloses a Microwave Integrated Circuit (MIC) Open Ring-Resonator Oscillator Combiner (Dual Oscillator) oscillating in the even mode. Such an oscillator improves over the prior art by simplifying the required circuitry, enhancing efficiency of operation, reducing losses, simplifying tuning and providing a graceful degradation backup capability.
In order to achieve synchronous operation, i.e., to operate with signals equal in phase and amplitude, the above referenced disclosed circuit requires the utilization of matched pairs of diodes.
The present invention further improves over the prior art and the referenced application by providing a circuit enabling the use of diodes having dissimilar impedances in an even mode, dual ring oscillator.